Stereotype plate casting machine



Dec. 2, 1947. o. c. ROESEN El AL STEREOTYFE PLATE CASTING MACHINE Fi led Dec 1944 5 Sheets-Sheet 1 ATTORNEYS Dec, 2, 1947. o. c. ROESEN ET AL 2, 3

STEREOTYPE PLATE CASTING MACHINE Filed Dec. 2, 1944 5 SheetsSheet 2 .7! 40 52 FIG. 3. w

I 77 F TMAGNETIC BRAKE INVENTORS OSCAR C. ROEEEN QQIARLES L. R'DCARDS ATTORNEYS Dec. 2, 1947. o. c. ROESEN El AL STEREOTYPE PLATE CASTING MACHINE Filed Dec.

5 Sheets-Sheet 4 FEG.7.

O C- ROESEN crig iifi LRKARDO i INVENTORS ATTORNEYS Dec. 2, 1947. o. c. ROESEN El AL STEREOTYPE PLATECASTING MACHINE 5 Sheets-Sheet 5 VENTORS ROE5EN CHARLE$ L. RICARDS ATTOR vans Patented Dec. 2, 1947 UNITED STATES PATENT OFFICE STEREOTYPE PLATE CASTING MACHINE Application December 2, 1944, Serial No. 566,328

Wood Newspaper 16 Claims.

This invention relates to an improved machine for casting stereotype plates.

Stereotype plates for use in printing newspapers and the like are made by casting molten metal in a mold in which a stereotype matrix, also known as a flong or mat, has been placed. The molten metal is solidified by cooling, and the resulting cast plate is separated from the matrix and finished.

The conventional mold consists essentially of a core and a casting box separated slightly from each other to provide the space in which the plate is cast, this mold space usually being arranged in a vertical position. In accordance with customary practice, the requisite amount of molten metal to form the desired cast plate is poured from the top of the mold into the space between the core and the casting box, the matrix having previously been placed therein. Such procedure, however, results in the production of a porous cast plate even though certain precautions are taken in the pouring of the molten metal, which appears to trap at least a portion of the air initially in such space in the form of bubbles. The air can only escape by being forced around and through the descending molten metal; and the cooling of the molten metal, which is solidified as quickly as possible since speed of operation is important, apparently does not permit all of the air to escape.

The present invention is directed to an improved stereotype plate-casting machine that avoids this operating difficulty. This improved machine is designed for the introduction of the molten metal into the bottom of the mold space so that the molten metal displaces the air upwardly substantially as a single mass as it rises as a pool within such space and does not trap any air as it solidifies. In this manner, intermingling of the molten metal being introduced into the mold space and of the air being displaced therefrom and the resulting porosity otherwise encountered are substantially avoided.

Our improved plate-casting apparatus includes a vertically arranged mold comprising a core and a casting box positioned at a slight elevation with respect to a metal-melting pot, the mold and the melting pot being interconnected by a suitable conduit for the introduction of the molten metal into the mold space at substantially the lowest point thereof. The introduction of the molten metal in this manner is controlled by a valve which is designed and operated so that the formation of a sprue on the cast plate by the metal in the connecting conduit is avoided and so that the molten metal in the connecting conduit is returned to the melting pot and any possible solidification of the molten metal in such conduit is thereby avoided. A particular feature of the invention resides in the coordination of the operation of this valve with the operation of the pump means for supplying the molten metal from the melting .pot to the mold space whereby the production of cast plates can be automatically or semiautomatically carried on without interruption. The improved machine may also be provided with means to enclose the top of the mold space, ordinarily left open, so that the air, as it is displaced upwardly in the mold space, is confined and exerts an increased pressure on the molten metal as it cools and solidifies whereby a close grain plate with finer detail is obtained. In this latter arrangement the mold space-enclosing means is advantageously provided with a release valve for the escape of the air confined in the mold space in accordance with any predetermined operating conditions.

Other features and advantages of the invention will be apparent from the following description of certain preferred forms thereof taken in connection with the accompanying drawings, in which:

Fig. 1 is an end elevation with parts in section and with certain parts omitted of a manually operated plate-casting machine provided with one form of the improved apparatus.

Fig. 2 is a side elevation with parts in section of the manually operated machine shown in Fig. 1, the machine being shown in this figure with the mold space filled with molten metal.

Fig. 3 is a detail view of a part of the machine taken along the line 33 of Fig, 1.

Fig. 4 is a diagram of the electric circuit for operating certain parts of the machine shown in Fig. 1.

Fig. 5 is a fragmentary side elevation, partially in section, showing the machine of Fig. 2 provided with a modified construction.

Fig. 6 is an end elevation with parts in section of an automatically operated plate-casting machine provided with another form of the improved apparatus.

Fig. 7 is a side elevation with parts in section of the machine shown in Fig. 6.

Figs. 8 and 9 are detail views taken along the line 8-8 of Fig. 6, the two figures showing the machine in successive operating positions.

The manually operated plate-casting machine shown in Figs. 1 and 2 includes the core l0 and the casting box II, which together form the mold in which the plates C and C are cast. This machine is so designed that, after the plate C has been cast, the casting box H is retracted and the core I is rotated through 180, during which rotation the top and the bottom of the plate are trimmed. The casting ,hox fll 'is then returned to its closed "position, the plate C leeing simultaneously dislodged from the core Ill, and the plate C is then cast in the mold space formed by the core and the casting box. I-hese operations are cyclically repeated until the desired number of plates has been cast.

The core 10 is journaled on the verticallshaft l2, the upper end of the core being formed "into a hub 13 which engages the upper'bearing it'd-of the shaft l2 and the lower .end of theacormbeing formed with the internal hub l which is fitted on the lower bearing 16 of the shaft I 2. "This shaft is provided at its lower end with the integrally tformed, outwardly extending iflang'e xh'l secured to the base I18. .Thezcore mests =nn rand :is supported by tlie'semicircular:ringrsupport 19, Iwhichtis also suitablysecured'ito lthe base of the machine. Rotation of the core :is accomplished through the bevel gear 220 secured :to the :upper hub l3 ofthe core and:driven:by the bevel rp'inion 21 mounted ion the shaft r122, whichis supported at one end by 17135 :bracket -23 carried by :the .frame 'member .24 affixed to the :base N8 :and which is :driven from any suitable mower source (not shown).

The :casting box 11! is'provide'd :on :each side with the rollers 25, which are adapted itozro'll along .the tops .of the frame members 26 .also secured :to .the base Inf the :machine. Jnumaled .in these frame membersiis the1shait'2:1.,nn nne .end :of 'which isflxed .thezhandlefQB. This .shalft also carries the icranks :29, 83.01). :of :which :is rpivotally connected to .one end rof an :arm c30Jin iturn pivotally fastened at its ntherend to.0n;e sideof the casting box. Upward-movement ."of :the :han-

dle 28 from the position shown in Fig. :2 e'fiects a retractionofthe casingEboX :11 from its ;closed position, ;and :movement .of this handle to the .position :shown 'efiects closing :of .the casting box.

The tail of the cast plate is trimmedzand the .lower edge thereof isalso trimmed, as .the :core H1 'is rotated, bysmea'ns of $118 :upper rand lower 'saws 3l and 32, respectively, :carried :on thershaft 33 journaledin the :bracket :34ipivotally 'mcunted on the framemember 24. .These saws are .oper- .ated by means of the belt :35 passing around the pulley "36 on :the shaft .33 and over .the guide pulley .31 and :driven by tanyfsuitablameans .(not shown). The .operation .of the .machine is such that the bracket 314 is swung'into operative .position only when thecastingibox H is retracted, the details of :such :mechanism being shown iin the patent to Wood, No. 1,009,272. Reference is also .made to this "patent .and to the Wood Patent .No. 11109367., :for other :details f construction andlopera'tion of ithe :casting rboxaand more.

In accordance with the .presentinvention, the metal-melting pot 38 is positioned below the :core and the casting box and may ibe lform'ed as a unit :therewith. This .potis provided \with the molten-metal .pump comprising ith'e .piston 39, the piston rod 40, and the piston cy-lin'der 4|, which-has 'the in'let openings *12 :and :the upwardly extending discharge .spout 43 that is fastened to a.1mani-fold 44 desirably formed "integrally -with the ring support l9. This manifoldidirects 4 the molten metal through an opening 45 into the arcuate passage '46 that communicates with the mold space in which the cast plate is formed.

Adapted to slide within this arcuate passage 46 is the similarly shaped gate valve 41 (Fig. 3), which controls the flow of the molten metal into the mold space. This valve .and the ring support 49 are respectively provided with the slots 48 and 49, in which is fitted the bifurcated end of the lever 50 pivotally mounted on the shaft 5.! .journaled in the extensions 52 of the ring support. 'The other end of the lever 50 is :pivotally connected by the pin 53 to one end of the arm 54, which in turn pivotally secured at its rather end to the crank 55 mounted on the crankshaft 58. Also mounted on this latter shaft is the worm gear 51 driven by the worm 58 secured to the drive shaft 59 of the motor 60. .As :indicated in Fig. 2, this motor is fastened to the base of the machine, and the shafts 56 and 59 are journaled in suitable hearings :in the housing 6| also secured-to the base :16.

The pistonzrod 4613f the molten-metal pump :is pivotally attached to one end of thelink fiz, the other end of which is in turn pivotally sezcured to the pump handle 63 mounted ion the shaft =64 rotatably journaled in the bracket =65 carried by .the .frame member 23. .Attached to this bracket 65 is the stop 66 which=engages one endof the latch rod 61 connected=at .its other :end to the latch handle 68 associated with the =pumpzhandle 63 in order to maintain the pump .piston 39 in the position shown in :Fig. .1 when the pump is not in use.

In-the operation of this plate-castingmachine, when :thecore and the casting box have been .brought together .and the valve 41 .has been opened as shown in Fig. 2, the latch rod .61 .is disengaged from the stop E56, the pump handle -53 is depressed, and the desired amount of molten metal is forced through the discharge spout 43 and the manifold '44 into the .mold space. .As the pump handle -63 reaches the bottom of itsstroke, the cam 69 mounted 1011 the shaft 6d trips the arm 10 of-the limit switch all .mounted on the .bracket 8'1 pivotallyjournaled .on the shaft 64 whereby an electric circuit is closed through energization of the operating solenoid 12 of the switch 12a and the motoris started (Fig. 4). The valve 41 is .thereby pushed upwardly'within the arcuate passage 46 and closes the opening -45 in the ring support L9, the molten metal being forced out of the passage 45 'so that no sprue is formed on the castplate .toiinterfere with the subsequent rotation of .the .core'l.-2. The pump handle 63 is now raised, and the molten metal remainingin the spout-43 and the :manifold M is returned to the melting pct 38 by gravity. The valve '4'! is provided with the internal vent line 73 open to the external atmosphere and communicating with the mani- .fold-44 when the valve is closed. This arrangement-lprevents'the formation of a vacuum'pocket in the spout -43 after the valvehas been closed and-so permits vtheimmediate return of molten metal .to the melting pot 38.

Closing of the valve 41 is accomplished by-rotation of the shaft 56 through half a revolution. As the .valve reaches its closed position, the cam '14 mounted on this shaft trips the arm 15 of the limit switch 16 secured in'the housing 6| whereby the motor-energizing circuit i broken through de-energization of the solenoid 12 and the motor 30 is stopped. A magnetic brake 1.1 of -known construction serves to stop the motorassoonas the circuit is broken. Although the limit switch H is opened when the pump handle 63 is raised, the motor circuit remains closed until the valve 41 reaches its closed position since the limit switch 16 closes as soon as the motor starts.

As soon as the cast plate has been sufliciently cooled, the casting box II is retracted by operation of the handle 29, and the core I9 is rotated through half a revolution for trimming of the cast plate and removal thereof for finishing. As the handle 29 is moved, the cam 18 fixed to the shaft 21 trips the arm 19 of the limit switch 89 mounted on one of the frame members 26 whereby the motor-energizing circuit is again closed through re-energization of the solenoid 12 of the switch 12a and the motor 69 is again started. The valve 41 is thereby moved to its open position as shown in Fig. 2 through rotation of the shaft 56 again through half a revolution. As the valve reaches its open position, the cam 14 again trips the arm 15 of the limit switch 19 whereby the circuit is again broken through deenergization of the solenoid 12 and the motor 69 is brought to a stop. The apparatus is then ready for the casting of another plate.

The amount of molten metal delivered to the v mold space may be varied as desired by adjustment of the knob BI on one end of the rod 82 journaled in the extension 83 of the bracket 23. The other end of this rod is threaded as shown at 84 and engages the threaded boss 85 to the bracket 81 carrying the limit switch 1 I. Such adjustment of the rod 92 changes the position of the pin 89 fixed in the limit-switch bracket 91 with respect to a slot 88 in the cam 99 so that the degree to which the pump handle 63 can be depressed is accordingly limited. The limit switch 1! is fixed in relation to the pin 86 and is similarly adjusted when the knob BI is turned so that the valve 41 is closed at the proper time regardless of the particular amount of molten metal delivered to the mold space.

In Fig. 5 there is shown a modified form of casting apparatus, in which the core I9 is provided with the annular sealing ring 99 suitably secured to its upper edge. This ring fits tightly against the casting box II and serves to confine the air initially within the mold space as the molten metal is introduced into the lower portion thereof. In this manner the hydrostatic pressure on the molten metal during the casting and cooling thereof is increased whereby a close grain plat with finer detail is obtained. In certain cases it may be possible, through such con finement and compression of the air within the mold space, to reduce the size of the tail customarily formed along the upper edge of the cast plate to provide the necessary hydrostatic pressure. Each half of this sealing ring 89 is equipped with an adjustable spring-loaded air-release valve 99 so that the degree of air compression within the mold space can be regulated.

The automatically operated plate-casting machine shown in Figs. 6 and 7 includes a cylindrical core 9! and a casting box 92. The cycle of operation of this machine is identical with that of the manually operated machine already described except that each operation is automatically carried out and, in accordance with the invention. the sequence of operations is automatically coordinated.

The lower portion of the core 9| is formed with a reentrant boss 9Ia, in which is suitably secured the verticallv disposed valve chamber 93 adapted to ride on the seat formed by the elbow-shaped conduit 9 3a fastened to the base 94 of the machine. Secured to the lower portion of the core is the ring 95, which corresponds to the ring support I9 of the manually operated machine and is provided with the vertical annular flange 96 surrounding the conduit 93a. The core is rotated as a unit with th ring 95, which may be formed integrally therewith, and with the valve chamber 93 about this conduit 93a, which acts as a guide therefor.

As in the manually operated machine, the metal-melting pot 91 is disposed below the core and the casting box and is provided with the moltenmetal pump comprising the piston 98, the piston rod 99, and the piston cylinder I99, which has the inlet openings MI and the upwardly extending discharge spout I 92 that is fastened to the extension I93 of the conduit 93a. The molten metal is forced up through the valve chamber 93, out through one of its two oppositely positioned ports I94 into the respective communicating cavity I95 (Fig. 8) formed between the core 9I and the ring 95, and into the mold space between the core and the casting box.

Adapted to slide within the valve chamber 93 is a valve piston I96 attached to the valve piston rod I91. This valve piston is provided, as shown in Fig. '7, with the depending arcuate boss I96a, which closes off the port I94 not in communication with the mold space so that the molten metal is directed only into such space.

The outer end of the rod I91 is pivotally fastened to one end of a rocker arm I98 secured at its other end to a shaft I 99 journaled in suitable bearings in the base of the machine. Also secured to this shaft I99 i the lever Il9 pivotally secured at its outer end to one end of the link I I I, the other end of which is bifurcated as shown in Fig. 7 and is provided with the roller I I2 adapted to slide in the cam groove I I3 of the cam plate H4 mounted on the shaft II5 journaled in the frame members I I6. This shaft I I5 is driven by the motor II1 through the sprocket chain II8 engaging the sprocket I I9 mounted on the motor shaft I29 and the sprocket I2I mounted on the shaft I22. The shaft I22 is suitably journaled in one of the frame members I I6 and carries a worm I23 that drives a worm wheel I 24 mounted on the shaft H5. The motor H1 is suitably supported from one of the frame members I I6.

The piston rod 99 of the molten metal-pump is pivotally attached to one end of the link I25, the other end of which is in turn pivotally attached to the crank I25 fixed to a stud I21 suitably journaled in the frame member I I6. Also fixed to this stud I21 is a throw lever I28 pivotally attached to one end of the arm I29 which is in turn pivotally secured at its other end to one arm of. the bell crank lever I39 mounted on the stud I3! also journaled in the frame member H6. The other arm of this bell crank has a roller I32 adapted to slide in the cam groove I33 in the cam plat I34 mounted on the shaft II 5. Ad- J'ustment of the amount of molten metal delivered to the mold space for the production of a cast plate can be obtained by varying the position of the arm I29 with respect to the throw lever I28, the pin I35 in the arm I29 engaging the slotted portion I36 of the throw lever I28 in the known manner.

The casting box 92 is provided on each side with the rollers I31 adapted to roll on the track members I38 secured to the respective frame members H6 during movement of the casting box to and from its closed position. The mecha- -nism :(not shown in .the interest :of clarity) for :so'moving the casting-box is alsodriven from the shaft lit! by nneans'of a cam arrangement, :and reference is made to the patent to Wood, No. 15848592, for the details of the construction and mperation thereof. The .mechanism for :rotating th :core, which .is enclosed 'within the housing 139, is also driven by the motor -l H in .a :coor- .dinated manner with the other .moving elements and is described in detail in this Wood :patent. Reference is also made 'to this patent zfor'details .of the 'upper :and lower tail-trimming saws I140 and MI mounted :on the shaft I4-2jjournaled in :the ltnza'cket I43 hingedly-isecured tonne of the zframe members .115, such :saws likewise .being driven from themotor zl l11in timed relation with the :rotation of the 'core, and :for other known details znot shown in the drawings.

:In'theoperationtof the described machine, when the :core :and the toasting ibox have been brought together and :the valve piston .is :in the open position as shown ?in .Fig. 6., the molten-metal :pump "forces :molten metal through "the valve chamber 93 and one of tthecavities -l05.into the bottom of the .mold space wherein it rises as a pool. soon as :thevprede'termined amount of :molten "metal :has ibeen forced into the mold spaceihexva'lve piston [.05is2automaticallyrmoved downwardly, thereby closing :ofi th cavity 105 fromthe'valvechamber :93; and the pump piston 98 is then depressed'whereuponthermolten metal remaining in' th'e'spout .162 and [the cconduit93a "is rreturned to theEOFQJibY gravity. '.Io;prevent the formation of a vacuum pocket in the .valve "chamber, the 'valve rpiston 4.0.6 is :provided with the internal air vent duct "M4 which ,matches with -one :of the air :vent :ducts il 45 in the valve :c'hamber 93, th core 1'9], and the string :95 when the waive pistontis'inits closed "p'ositiongthe vent ducts i hiibeing open -to-the external atmosphere. Each vent duct I45 .is also -provided with the extension I48 opening into the espacetaboveithe valvepiston E06.

When the valve piston i116 has :been "closed, during which time the cast plate is being cooled '-to'so'lidify the molten metal, the casting box "92 "is automatically retractedth'e core :9! is rotated through 181)", and the saws *Mltand H41 'trim the upper and "lower tails T and T, respectively, from the cast plate as thecore is rotated. "The casting box is then returned toits closed position whereupon the cast plate-C and its upper tail T are broken away from the core and :removed. 'Thelower tail T is removed by means of the fingers MT, which are attached to the lower portion of the casting box and'which *contact the projections M8 of the ejector bars 149 sliding in corresponding grooves in the lower part of the core 9|, such projections extending downwardly through the slot-like openings I50 in the ring 95 (Figs '8 and 9). Inthis manner the elector'bars contact the lower tail'T' and dislodge it fromthe cavity I85 so that it can be removed 'from the machine. Fig. 8 shows the 'tail T ready TtO be ejected, and Fig. 9 shows this tail in ejected position. 'In the meantime the valve piston "[06 is again movedto its-open position as shownyand the machine is ready to form another cast plate. As already indicated, the several operations are all automatically coordinated by means :of the 'several'cam plates and related mechanismawhich are so designed that each operation is performed in -timed sequence in relation to'the others.

As in the case of the manually operated -machine, this automatic machine may :also be ;provided withthe sealing ring I 51 secured to the upper edge of the score 9|. Spring locked adjustable air-release valves l5la, similar to the valves of the manually operated-machine, may be provided onthe ring IE! to control the'pressure to which air is compressed in the mold space. .Brovision (not shown) is, of course, made for the -introduction of the requisite cooling water, \which :is removed ".from the core through the nipples 152 and the 'drain pipe I53.

Although the present invention has been -.described in detail in connection with the above types of platecasting machines, it is applicable toother typesof such machines and also to the productionof other types of plates such as flat .plates.

We claim:

1. =In combination with :a stereotype platecasting machine including a vertical mold comprising acore and a casting box forming a ver- 17108.1 'mold space therebetween, .a metal-melting pot-below the bottom of the mold, a conduit con- .necting the melting pot with the bottom of the mold space, a cut-ofi valve interposed :between the head of the conduit and the bottom of the mold space for blocking the passage from the conduit to the mold space, and means operated bythe valve to vent the head of the conduit below the valve-when the valve is closed andto close such vent when the valve is open.

2. 'In combination with a stereotype :platecastingmachine including-a vertical mold comprising .a-cylindrical core and a semicyclindrical casting-box forming a vertically extending mold space therebetween, a metal-melting pot below the lower-end of the mold, an arcuate member tier-supporting the core, a manifold carried by the arcuate member and communicating with the bottom :of the mold space, a conduit connecting the melting pot and the manifold, a valve inter- ;posed between the melting pot and the mold space for controlling the flow of molten metal through-the conduit into such space and means operated by said valve for venting said'conduit to atmosphere only when said-valve is closed.

-3. 'In combination with a stereotype plate- .casting machine including a vertical mold 'com prising a cylindrical core and a semicylindrical casting box forming a vertically extending mold space therebetween, a metal-melting pot below the bottomof said mold, an arcuate member for supporting the core, said arcuate member 'havingra, vertical arcuate passage inalinement -pe- -.ripherally with the bottom of the mold space, .a manifold carried by the arcuate-member and :communicating with the arcuate passage, a-con- 'duit connecting the melting pot and the manii feldganda valve slidable in the arcuate passage .to'control the flow of molten metal into the mold rspace.

4. in combination with a stereotype "platecasting machine including a vertical mold comprising a cylindrical core and a semicyclindrical 'casting box forminga vertically extending mold 'space therebetween, a metal-melting pot below the .bottom of said mold, vertical chamber positioned below the core and arranged axially with srespect thereto, said core being formed to provide a passage between the chamber and the bottom of the mold space, a conduit connecting the melting pot and the chamber, and a valve interposed between the melting pot and the mold 'space for controlling the flow of molten metal into such space.

5. In combination with a "stereotype plate- 9 casting machine including a vertical mold comprising a cylindrical core and semicylindrical casting box forming a vertically extending mold space therebetween, a metal-melting pot disposed below the bottom of the mold, a vertical valve chamber associated with the bottom of the core and arranged axially with respect thereto, said core being formed to provide a passage between the valve chamber and the bottom of the mold space, a conduit connecting the melting pot and the valve chamber, and a valve movable in said valve chamber for controlling the flow of molten metal into the mold space.

6. In combination with a stereotype platecasting machine including a vertical mold comprising a cylindrical core rotatable about a vertical axis and an arcuate casting box adjacent a part of the cylindrical surface of the core and forming therewith a vertically extending mold space, 9, metal-melting pot below the mold, a valve chamber secured to the bottom of the core and arranged axially with respect thereto, said core being formed to provide oppositely disposed passages alternately connecting the chamber with the bottom of the mold space when the core is rotated, a conduit connecting the meltinfi pot and the chamber, said chamber having oppositely disposed openings each communicating with one of the core passages, and a valve movable in the chamber for controlling the flow of molten metal from said chamber and into the mold space through the one of said core passages connecting said chamber to the mold space.

'7. In combination with a stereotype platecasting machine including a vertical mold comprising a core and a casting box forming a vertically extending mold space therebetween, a conduit communicating with the bottom of the mold space, means to introduce molten metal through the conduit into the mold space, a cutoff valve interposed between the conduit and mold space for blocking the passage therethrough, a sealing member for closing the top of the mold space to confine air therein under compression as the molten metal rises within such space, and a loaded air-release valve positioned across a passage through the sealing member for releasing confined air in said space.

8. In combination with a stereotype platecasting machine including a vertical mold comprising a cylindrically shaped core and a semicylindrical casting box forming a vertically extending mold space therebetween, a conduit communicating with the bottom of the mold space, means to introduce molten metal through the conduit into the mold space, a cut-off valve interposed between the conduit and mold space for blo king the passage therethrough, an annular sealing ring for closing the top of the mold space to confine air therein under compression as the molten metal rises within such space, said sealing ring being attached to the upper peripheral edge of the core, and a loaded air-release valve positioned across a passage through the sealing ring for permitting the escape of such confined air.

9. In combination with a stereotype plate-casting machine including a vertical mold comprising a cylindrical core and a casting box forming a vertically extending mold space therebetween, said core being rotatable about its vertical axis and said casting box being retractible from its closed position with respect to the core, a vertical chamber positioned below the core and arranged axially with respect thereto, the lower portion of said core being formed to provide a passage between the chamber and the bottom of the mold space, means to introduce molten metal into the mold space through the chamber and the passage, a valve to control the flow of molten metal into the mold space, the molten metal forming in said passage a tail on the plate cast in the mold space, means to trim the tail from the cast plate during rotation thereof with the core, and means operable by movement of the casting box for dislodging the severed tail from the passage.

10. In combination with a stereotype platecasting machine including a vertical mold comprising a core and a casting box forming a vertically extending mold space therebetween, said core being rotatable about its vertical axis and said casting box being retractible from its closed position with respect to the core, a vertical chamber positioned below the core and arranged axially with respect thereto, the lower portion of said core being formed to provide a passage between the chamber and the bottom of the mold space, means to introduce molten metal into the mold space through the chamber and the passage, a valve to control the flow of molten metal into the mold space, the molten metal forming in said passage a tail on the plate cast in the mold space, means to trim the tail from the cast plate, ejector means associated with the core and adapted to engage the severed tail, and inwardly projecting means on the casting box for engaging said ejector means upon closing of the casting box from its retracted position and causing the ejector means to engage the severed tail for dislodgement thereof from the passage.

11. In combination with a stereotype plates. casting machine including a vertical mold comprising a core and a casting box forming a vertically extending mold space therebetween, a conduit communicating with the bottom of the mold space, a pump for introducing a plate forming charge of molten metal through the conduit into the mold space in one discharge stroke, means for operating the pump, a cut-off valve interposed between the conduit and the bottom of the mold space for blocking the passage therethrough, and means positively operated by the pump operating means at the end of the pump discharge stroke for closing the valve.

12. In combination with a stereotype platecasting machine including a vertical mold comprising a core and a casting box forming a vertically extending mold space therebetween, said casting box being retractible from its closed'position with respect to the core, a conduit oommunicating with the bottom of the mold space, means to introduce a plate forming charge of molten metal through the conduit into the mold space, a cut-01f valve interposed between the conduit and the bottom of the mold space for blocking the passage therethrough, means positively operated by the molten metal-introducing means for closing the valve immediately after the plate forming charge of molten metal has been introduced into the mold space, means to retract the casting box, and means positively operated by the casting box in its retracted position for opening the valve.

13. In combination with a stereotype platecasting machine including a vertical mold comprising a core and a casting box forming a vertically extending mold space therebetween, said casting box being retractible from its closed position with respect to the core, a conduit communieating with the bottom of the mold space, a pump for introducing a plate forming charge of molten gizing itself when the valve is closed, means to retract the casting box, means operable by mcvement of the casting boxto its retracted position for re-energizing the motor to open the valve, and means operable by the motor to de-energize itself when the valve is opened.

14. In combination with a stereotype platecasting machine including a vertical mold comprising a core and a'casting box forming a vertically extending mold space therebetween, a'conduit communicating with the bottom of the mold space, means to introduce molten metal through the conduit into the mold place, a cut-oil? valve interposed between the conduit and the bottom of the mold space for blocking the passage therethrough, a driving means, and means operable by said driving means positively for operating the molten metal-introducing means, immediately closing the valve, and positively opening the valve in timed sequence.

15. The combination with a stereotype plate casting machine including a vertically extending mold comprising a core and a casting box forming a vertically extending mold space therebetween, a metal melting pot below the bottom of the mold, a conduit connecting the melting pot with the bottom of the mold space, a cut-ofi valve interposed between the conduit and the bottom of the mold space for blocking the passage therethrough and including a movable valve element, and a vent including a passage in said valve element for venting the conduit below said valve to the atmosphere only when said valve is closed.

16. The combination with a stereotype plate 12 casting machine including a vertically extending mold comprising a core and a casting box forming a vertically extending mold space therebetween, a metal melting pot below the bottom of the mold, a conduit connecting the melting pot with the bottom of the mold space and forming an upwardly extending path to conduct metal from the melting pot to the mold space, a cutofi valve interposed between the conduit and the bottom of the mold space for blocking the passage therethrough and to permit the immediate return flow of molten metal from the conduit below the valve to the melting pot, and a vent for venting the conduit below said valve to the atmosphere only when said valve is closed.

OSCAR C. ROESEN.

CHARLES L. RICARDS.

REFERENCES CITED The following references are of record in the file of this patent:

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